// Copyright (c) 2021 Dmitry Meduho
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// Notwithstanding the foregoing, you may not use, copy, modify, merge, publish,
// distribute, sublicense, create a derivative work, and/or sell copies of the
// Software in any work that is designed, intended, or marketed for pedagogical or
// instructional purposes related to programming, coding, application development,
// or information technology.  Permission for such use, copying, modification,
// merger, publication, distribution, sublicensing, creation of derivative works,
// or sale is expressly withheld.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

import AppKit

// MARK: - Protocols

public protocol DragAnimatedImageViewDelegate: AnyObject {
    func canBeDragged(_ dragAnimatedImageView: DragAnimatedImageView) -> Bool
    func beginDragginSession(for dragAnimatedImageView: DragAnimatedImageView, event: NSEvent)
}

// MARK: - Enums, Structs

extension DragAnimatedImageView {
    private enum Constants {
        static let dragThreshold: CGFloat = 3.0
    }
}

// MARK: - Class

public final class DragAnimatedImageView: AnimatedImageView {
    public override func mouseDown(with event: NSEvent) {
        super.mouseDown(with: event)
        
        guard isEnabled else {
            return
        }
        
        guard let delegate = dragDelegate, delegate.canBeDragged(self) else {
            return
        }

        let location = convert(event.locationInWindow, from: nil)
        let eventMask: NSEvent.EventTypeMask = [.leftMouseUp, .leftMouseDragged]
        let timeout = NSEvent.foreverDuration

        window?.trackEvents(matching: eventMask, timeout: timeout, mode: .eventTracking) { event, stop in
            guard let event = event else {
                return
            }
            switch event.type {
            case .leftMouseUp:
                stop.pointee = true

            case .leftMouseDragged:
                let movedLocation = convert(event.locationInWindow, from: nil)
                if abs(movedLocation.x - location.x) > Constants.dragThreshold || abs(movedLocation.y - location.y) > Constants.dragThreshold {
                    stop.pointee = true
                    delegate.beginDragginSession(for: self, event: event)
                }

            default:
                break
            }
        }
    }
    
    // MARK: - Public

    public weak var dragDelegate: DragAnimatedImageViewDelegate?
}
